My top suggestion is AudioEngine 5+ speakers.  They are $399 for a new pair, and are powered speakers (so no external amp needed).  They somewhat exceed your price target, but you might find the previous version (5, not the 5+) for less.  There's no audio difference between the versions.  But they meet your online criteria (they sell online direct, as well as through online vendors such as Crutchfield), and your simplicity criteria definitely, and your quality criteria definitely (read the enthusiastic reviews from many sources), and your size criteria.

If you want to just spend $200, get the smaller ones, the AudioEngine 2's.

Or consider the Adam F5 powered speaker, around $300, available online through Guitar Center and others.

There are other good choices out there, and others may recommend passive speakers with an amp.  That's a good way to go, too, but somewhat less simple.